COLLECTIONS : On the Up and Up : Paris: Azzedine Alaia is clearly torn between the lady and the vamp in his spring designs.

Azzedine Alaia revealed a new, unexpected side of his ideal women in his spring ’91 collection shown here last week. Long established as a vamp, she now appears to have a ladylike side as well.

Since his first Paris show in 1981, Alaia has featured haute -corset looks and hip-length stretch dresses and skirts with the focus on black, white and unusual pastels such as seafoam green. But this season, besides hot pants and miniskirts in black-and-white houndstooth checks, there were warmer colors, especially raspberry, and mid-calf hemlines that represent a classically feminine option.

After his show he said that Tati, a popular chain of French discount stores, was a main inspiration for the new collection. Tati’s corporate symbol is its name emblazoned on a background of red and white gingham. One strong example of the connection was a gingham-check halter top over skintight clam diggers in raspberry and ivory stretch canvas. The pants had football shoe lacings in back.

Alaia’s elegant but carefree eveningwear was the surprise. A long, airy, white chiffon dress with gold-chain shoulder straps drew the loudest applause. Other luxuriously draped and pleated styles were shown over hot pants and bustiers.

This season, when fears of terrorism have cut international travel, none of Alaia’s three superstar model regulars--Naomi Campbell, Linda Evangelista and Christy Turlington--appeared on the runway. But there were several items in the collection that they could wear well: fanny-baring python hot pants, matching blousons and leather halter tops.

But the new collection indicates an usually strong interest in dressing his customer on those occasions when such an ensemble might not be appropriate.